Human hair becomes soiled due to its contact with the surrounding environment and from the sebum secreted by the scalp. The soiling of hair causes it to have a dirty feel and an unattractive appearance. The soiling of the hair necessitates shampooing with frequent regularity.
Shampooing cleans the hair by removing excess soil and sebum. However, shampooing can leave the hair in a wet, tangled, and generally unmanageable state. Once the hair dries, it is often left in a dry, rough, lusterless, or frizzy condition due to removal of the hair's natural oils and other natural conditioning and moisturizing components. The hair can further be left with increased levels of static upon drying, which can interfere with combing and result in a condition commonly referred to as “fly-away hair.”
A variety of approaches have been developed to alleviate these after-shampoo problems. These approaches range from post-shampoo application of hair conditioners such as leave-on and rinse-off products, to hair conditioning shampoos which attempt to both cleanse and condition the hair from a single product.
In order to provide hair conditioning benefits in a cleansing shampoo base, a wide variety of conditioning actives have been proposed. However, many of these actives have the disadvantage of leaving the hair feeling soiled or coated and of interfering with the cleansing efficacy of the shampoo.
Coacervate formation in a shampoo composition is known to be advantageous for providing conditioning benefits to the hair. The use of cationic polymers to form coacervate is known in the art, such as in PCT publications WO 93/08787 and WO 95/01152. However, these shampoo compositions are good for delivering wet hair conditioning but are not capable of delivering satisfactory dry hair smooth feel.
Based on the foregoing, there is a need for a conditioning shampoo which can provide improved conditioning benefit for dry hair, while not interfering with the cleansing efficacy, nor providing negative feel to the hair when it is dried. Specifically, there is a need to provide long lasting moisturized feel, smooth feel, and manageability control to the hair when the hair is dried, yet not leave the hair feeling greasy, as well as to provide softness and ease of combing when the hair is wet.
Recently, the use of shampoo compositions comprising a dispersed fatty alcohol gel network phase has been proposed to achieve improved wet feel and dry conditioning benefit while not interfering with cleansing efficacy. In such shampoo compositions, the fatty alcohol is in the form of a solid crystalline gel network phase, meaning that the fatty alcohol is arranged in multi-lamellar vesicles and lamellar sheets in the dispersed phase. It is believed that this physical structure of the gel network allows the fatty alcohol to deposit on the hair in sheets, with the fatty ends of the fatty alcohol molecules aligning away from the hair and forming a low friction surface, which contributes to the improved conditioning benefit. For use in such shampoo compositions, U.S. 2003/0223952 A1 to Wells et al. (“Wells”) discloses that fatty alcohols having from about 16 to about 18 carbon atoms are most preferable. Additionally, Wells exemplifies only shampoo compositions comprising combinations of cetyl (i.e., C16) alcohol and stearyl (i.e., C18) alcohol.
While this approach leads, generally, to achieving the described benefits, it has now been found that shampoo compositions comprising a dispersed fatty alcohol gel network phase, wherein the dispersed fatty alcohol gel network phase has a melt transition temperature of at least about 38° C., are most storage stable under standard physical stability protocols and surprisingly also deliver superior dry conditioning benefits versus shampoo compositions such as those disclosed as preferable and exemplified in Wells.